A long while back I was hanging out with one of my sisters and she said that she hears thunder in her head when she gets startled.
Me: “Scuse me. What?”
Her: “You know. That thunder you hear when someone startles you.”
Me: “Again. What?”
Her: “You don’t hear thunder when someone startles you?”
Me: “Uh, no.”
Her: “Oh. I thought that happened to everybody.”
Is this a thing? Does this happen to anybody else out there? She did struggle with depression for much of her life. Could that have had something to do with it?
I had to dig up my old neuroscience notes. After my notes this is called “Synesthesia”. “[It] is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway” (Wikipedia).
After my notes only 1 in 25’000 people (Cytowic, 1988) have that. And after Wikipedia the effect vary strongly.
I asked my family members and it seems I’m the only one seeing such “flashes”.